Insulation performance of permittivity graded FGM (functionally graded materials) in SF/sub 6/ gas under lightning impulse conditions

For the size reduction of electric power apparatus, the electric field stress around solid insulators is increasing and carefully to be considered. This concern may be solved by the application of FGM (functionally graded materials). In this paper, we investigated the insulation performance of FGM insulator, from both experimental approach and numerical simulation. Firstly, we fabricated column and truncated cone spacers having the permittivity distributed characteristics. Secondly, we investigated the breakdown in SF₆ gas under lightning impulse conditions with theoretical discussion. Finally, we could verify the insulation performance of FGM, and confirmed the significant effect of FGM application for gas/solid composite insulation system